Problem with DIY CNC


Author Message
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 1865
Posted: 08:02am 21 Apr 2023      

One possible mechanical solution could be a counterweight for the motor. It would be a bit clumsy though. The middle of the counterweight arm would require a support pillar attached to the Z-axis support beam (X or Y axis) and a linkage from the end of the arm down to the spindle motor body.

One possible electrical solution could be increasing the width of the stepper pulses. The increased overlap between phases might reduce the tendency to overshoot after a step. Combined with slowing down the decent rate to reduce momentum might be just enough.

Edit
A electromechanical solution might be a counter-force motor. A small DC motor with a bobbin on the shaft, attached to the Z-axis support. Thread from the bobbin is attached to the to the spindle motor body. A resistor in series with the motor limits its torque to just counteract the mass of the spindle motor.

Edit 2
Or use a bigger Z-axis stepper motor. Hopefully it will have greater holding torque.

Another mechanical method would be reduction gears between the Z-axis and it's stepper motor. This would reduce the load on the motor at the expense of more steps per mm.
Edited 2023-04-22 09:08 by phil99